Point thermal individual and so on block. Block heat points. What are the benefits of installing a BTP

18.10.2019

S. Gromov, Ph.D., A. Panteleev, Ph.D., A. Sidorov, Ph.D.

The transition of the economy to market relations is characterized by a sharp increase in competition. One of the decisive factors that allow producers of goods and services to survive in a competitive environment is the reduction of production costs. In turn, production costs (or operating costs) are a fundamental indicator that determines the cost.

Water treatment costs is an integral part of operating costs energy enterprises and petrochemical complexes. The task of reducing operating costs for water treatment is complicated by the growth of tariffs for water use; continuous deterioration of water quality (for example, an increase in salinity) in sources suitable for industrial use; already sharpened standards for quantitative and qualitative indicators for discharged wastewater; increasing requirements for the quality of treated water used in the technological cycle.

Decide the task of reducing operating costs for water treatment allows the introduction of new technologies. Speaking about modern approaches to solving water treatment problems, it is necessary, first of all, to single out membrane technologies for water treatment: ultra- and nanofiltration , reverse osmosis, membrane degassing and electrodeionization of water.

Based on these processes, it is possible to implement the so-called integrated membrane technologies (IMT), the use of which allows to reduce the operating costs for water treatment, despite Negative influence any of the above factors.

Let us illustrate the last statement with an example of solving the problem of obtaining demineralized water (with a residual electrical conductivity of not more than 0.1 μS/cm) in the case when the source is river surface water.

The traditional method for solving this problem is to use technological scheme water treatment shown in fig. 1. In fig. 2 you can see what an alternative solution using "integrated membrane technologies" looks like.

Ultrafiltration provides surface water pretreatment before further demineralization. Using water ultrafiltration, replacing the stages of liming with coagulation and clarification filtration, the consumption of reagents is sharply reduced, water consumption for own needs is less than 10% (often in the range of 2-5%), and there are no suspensions and colloids in the filtrate.

The given data allow us to evaluate the economic efficiency of the use water ultrafiltration compared to traditional pretreatment.

Use of technology reverse osmosis(or nanofiltration in combination with reverse osmosis) for the purposes of water demineralization also provides a number of advantages over the traditional two-stage parallel-current ionization scheme:

firstly, the use of membrane technologies is not accompanied by the consumption of a large amount of reagents (acids and alkalis) for regeneration;
second, excluded education highly mineralized wastewater caused by the release of excess reagents during regenerations;
thirdly, a significantly higher degree of removal of organic compounds (including non-polar ones) and colloidal flint from the treated water is achieved than with ion exchange;
Fourth, there is no need neutralization discharged wastewater.

Thus, operating costs when using membrane methods of water treatment are significantly lower than in the case of traditional ionization technology. On fig. 3 shows the so-called point of economic equilibrium of operating costs when using membrane and ion-exchange technologies for water demineralization, depending on the value of the salinity of the source water. Note that in this case it was assumed that countercurrent regeneration technology is used for ion exchange(for example, APCORE, whose costs for reagents are 1.5-2 times lower than with parallel flow regeneration).

It should be noted that under modern conditions, desalination plants, the principle of which is based on the use of the evaporation process (thermal distillation), are unlikely to be able to compete in terms of operating costs with BMI for treating water with a salt content of up to 2 g/l. The cost of demineralized water obtained by the thermal distillation method will be at least 30 rubles/m3, even if we assume that heat losses during evaporation will be at the theoretical minimum level, and the cost of 1 Gcal is 200 rubles.

Finally, electrodeionization of water, being reagentless and drainless membrane water treatment technology, provides residual electrical conductivity of demineralized water at the level of 0.08 μS/cm. Obviously, the operating costs for electrodeionization will also be lower than for FSD. True, it should be noted that the stability of the performance of the water electrodeionization installation depends on how well the reverse osmosis system: in the event of failures in the operation of the latter, the inevitable consequence will be a decrease in the efficiency of the water electrodeionization process.

Taking into account this circumstance, instead of electrodeionization (for cases when it is required to ensure the highest degree of reliability of the technological scheme of water desalination), countercurrent H-OH-ionization or FSD can be used.

If the variant with FSD is more preferable in terms of saving reagents during regeneration, then countercurrent H–OH ionization is preferable for reasons of ease of automation and ease of operation. In addition, if the H-OH-ionization unit provides use of APCORE technology, then the technological scheme acquires an additional degree of stability and can be operated even under conditions bypass reverse osmosis.

By itself, the technology of countercurrent regeneration of APCORE ion exchangers is successfully used in cases where the consumer intends to confine himself only to the reconstruction (in countercurrent) of the existing parallel-precise ion exchange water treatment plant, or under conditions when the value of the salinity of the source water is consistently below 100 mg/l, and non-polar organics and colloidal flint are present in it in negligible amounts.

Considering the problem of water softening, it is worth mentioning the scheme in which nanofiltration is accompanied by additional softening on sodium-cation-exchange filters.

Due to the ability of nanofiltration membranes to retain polyvalent ions well, nanofiltration is successfully used to solve water softening problems. If, due to the high hardness of the source water, nanofiltration does not provide the required degree of water softening, the filtrate is sent to sodium-cationite filters for additional softening. Moreover, these filters operate both in the countercurrent regeneration mode (for example, APCORE) and in the parallel flow mode, if the frequency of regeneration of sodium cation exchange filters is low (for example, less than twice a month).

AT last years more and more clearly the desire of consumers recycle waste water for the purpose of their reuse in the technological cycle. At the same time, traditional tasks solved by using membrane technologies (most often - ultrafiltration combined with reverse osmosis), are a reduction in the volume of discharged Wastewater and reducing the consumption of water abstracted from natural sources.

At the same time, application membrane technologies for water treatment makes it possible to approach the solution of another very important environmental problem - a sharp reduction in the consumption of salt used for the regeneration of existing ion-exchange water softening filters. This goal is achieved by reusing saline effluent after treatment to regenerate sodium cation filters.

Water is essential for human life and all life in nature. Water covers 70% earth's surface, these are: seas, rivers, lakes and groundwater. During its cycle determined by natural phenomena, water collects various impurities and pollution that are contained in the atmosphere and on the earth's crust. As a result, water is not absolutely pure and pure, but often it is this water that is the main source for both domestic and drinking water supply and for use in various industries industry (for example, as a coolant, working fluid in the energy sector, solvent, feedstock for products, food, etc.)

Natural water is a complex dispersed system, which contains a variety of mineral and organic impurities in large quantities. Due to the fact that in most cases the sources of water supply are surface and groundwater.

The composition of ordinary natural water:

suspended solids (colloidal and coarse mechanical impurities of inorganic and organic origin);
bacteria, microorganisms and algae;
dissolved gases;
dissolved inorganic and organic substances (both dissociated into cations and anions, and undissociated).

When assessing the properties of water, it is customary to divide the water quality parameters into:

physical,
chemical
sanitary and bacteriological.

Quality is understood as compliance with the standards established for this type of water production. Water and aqueous solutions are widely used in various industries, utilities and agriculture. Requirements for the quality of purified water depend on the purpose and scope of treated water.

The most widely used water for drinking purposes. The requirements in this case are determined by SanPiN 2.1.4.559-02. Drinking water. Hygiene requirements to water quality centralized systems drinking water supply. Quality control" . For example, some of them:

Tab. 1. Basic requirements for the ionic composition of water used for domestic and drinking water supply

For commercial consumers, water quality requirements are often tightened in some respects. So, for example, for the production of bottled water, a special standard has been developed with more stringent requirements for water - SanPiN 2.1.4.1116-02 “Drinking water. Hygienic requirements for the quality of water packaged in containers. Quality control". In particular, the requirements for the content of basic salts and harmful components - nitrates, organics, etc. have been tightened.

Water for technical and special purposes is water for use in industry or for commercial purposes, for special technological processes - with special properties regulated by the relevant standards of the Russian Federation or the technological requirements of the Customer. For example, preparation of water for energy (according to RD, PTE), for electroplating, preparation of water for vodka, preparation of water for beer, soft drinks, medicine (pharmacopoeia article), etc.

Often the requirements for the ionic composition of these waters are much higher than for drinking water. For example, for thermal power engineering, where water is used as a heat carrier and is heated, there are relevant standards. For power plants, there are so-called PTE (Rules technical operation), for the general thermal power industry, the requirements are set by the so-called RD (Guiding Document). For example, according to the requirements Guidelines on supervision of the water-chemical regime of steam and hot water boilers RD 10-165-97 ”, the value of the total hardness of water for steam boilers with an operating steam pressure of up to 5 MPa (50 kgf / cm2) should be no more than 5 μg-eq / kg. At the same time drinking standard SanPiN 2.1.4.559-02 requires that Jo be no higher than 7 meq/kg.

Therefore, the task of chemical water treatment (CWT) for boiler houses, power plants and other facilities that require water treatment before heating water is to prevent the formation of scale and the subsequent development of corrosion on the inner surface of boilers, pipelines and heat exchangers. Such deposits can cause energy losses, and the development of corrosion can lead to a complete shutdown of boilers, heat exchangers due to the formation of deposits on the inside of the equipment.

It should be borne in mind that the technologies and equipment for water treatment and water treatment for power plants differ significantly from the corresponding equipment for conventional hot water boilers.

In turn, the technologies and equipment for water treatment and water treatment for obtaining water for other purposes are also diverse and are dictated by both the parameters of the source water to be treated and the requirements for the quality of treated water.

SVT-Engineering LLC, having experience in this field, having qualified personnel and partnerships with many leading foreign and domestic specialists and firms, offers its customers, as a rule, those solutions that are expedient and justified for each specific case, in in particular, based on the following basic technological processes:

The use of inhibitors and reagents for water treatment in various systems CWT (both to protect membranes and thermal power equipment)

Most water treatment processes various types, including sewage, have been known and used for a relatively long time, constantly changing and improving. Nevertheless, leading specialists and organizations around the world are working on the development of new technologies.

LLC "SVT-Engineering" also has experience in conducting R&D at the request of customers in order to increase efficiency existing methods water purification, development and improvement of new technological processes.

It should be especially noted that the intensive use of natural water sources in economic activity necessitates the environmental improvement of water use systems and technological processes of water treatment. The requirements for the protection of the natural environment require the maximum reduction of waste from water treatment plants into natural water bodies, soil and atmosphere, which also makes it necessary to supplement the technological schemes of water treatment with stages of waste disposal, their processing and conversion into recyclable substances.

To date, a sufficiently large number of methods have been developed that allow the creation of low-waste water treatment systems. First of all, these include improved processes for preliminary purification of source water with reagents in clarifiers with lamellas and sludge recirculation, membrane technologies, demineralization based on evaporators and thermochemical reactors, corrective water treatment with inhibitors of salt deposits and corrosion processes, technologies with countercurrent regeneration of ion exchange filters and more advanced ion exchange materials.

Each of these methods has its advantages, disadvantages and limitations of their use in terms of the quality of source and treated water, the volume of effluents and discharges, and the parameters of treated water use. You can get additional information necessary to solve your problems and terms of cooperation by making a request or by contacting the office of our company.

This section describes in detail the existing traditional water treatment methods, their advantages and disadvantages, as well as presents modern new methods and new technologies to improve water quality in accordance with consumer requirements.

The main tasks of water treatment are to obtain clean, safe water suitable for various needs at the outlet: household, drinking, technical and industrial water supply taking into account the economic feasibility of applying the necessary methods of water treatment, water treatment. The approach to water treatment cannot be the same everywhere. The differences are due to the composition of water and the requirements for its quality, which differ significantly depending on the purpose of the water (drinking, technical, etc.). However, there is a set of typical procedures used in water treatment systems and the sequence in which these procedures are used.

Basic (traditional) methods of water treatment.

In the practice of water supply, in the process of purification and treatment, water is subjected to clarification(exemption from suspended particles), discoloration ( removal of substances that give color to water) , disinfection(destruction of pathogenic bacteria in it). At the same time, depending on the quality of the source water, in some cases, special methods for improving the quality of water are additionally applied: softening water (reduction of hardness due to the presence of calcium and magnesium salts); phosphating(for deeper water softening); desalination, desalination water (decrease in the total mineralization of water); desilting, deferrization water (liberation of water from soluble iron compounds); degassing water (removal of soluble gases from water: hydrogen sulfide H 2 S, CO 2 , O 2); deactivation water (removal of radioactive substances from water.); neutralization water (removal of toxic substances from water), fluorination(adding fluoride to water) or defluoridation(removal of fluorine compounds); acidification or alkalization ( for water stabilization). Sometimes it is necessary to eliminate tastes and odors, prevent the corrosive effect of water, etc. These or other combinations of these processes are used depending on the category of consumers and the quality of water in the sources.

The quality of water in a water body and is determined by a number of indicators (physical, chemical and sanitary-bacteriological), in accordance with the purpose of water and established quality standards. More about it in the next section. By comparing the water quality data (obtained from the results of the analysis) with the requirements of consumers, measures for its treatment are determined.

The problem of water purification covers the issues of physical, chemical and biological changes in the process of processing in order to make it suitable for drinking, i.e. cleaning and improving it natural properties.

The method of water treatment, the composition and design parameters of treatment facilities for industrial water supply and the estimated doses of reagents are established depending on the degree of pollution water body, the purpose of the water supply, the performance of the station and local conditions, as well as on the basis of data from technological studies and the operation of facilities operating in similar conditions.

Water purification is carried out in several stages. Debris and sand are removed at the pre-cleaning stage. The combination of primary and secondary treatment, carried out in a water treatment plant (WTP), allows you to get rid of colloidal material (organic substances). Dissolved nutrients are removed by post-treatment. In order for the treatment to be complete, the wastewater treatment plant must eliminate all categories of pollutants. There are many ways to do this.

With appropriate post-treatment, with high-quality WTP equipment, it is possible to achieve that, in the end, water suitable for drinking will be obtained. Many people turn pale at the thought of reusing sewage, but it is worth remembering that in nature, in any case, all water cycles. In fact, appropriate post-treatment can provide water best quality than obtained from rivers and lakes, which often receive untreated sewage.

The main methods of water treatment

Water clarification

Clarification is a stage of water purification, during which the turbidity of water is eliminated by reducing the content of suspended mechanical impurities in it of natural and waste water. The turbidity of natural water, especially surface sources during the flood period, can reach 2000-2500 mg/l (at the norm for drinking water - no more than 1500 mg/l).

Clarification of water by sedimentation of suspended solids. This function is performed clarifiers, settlers and filters, which are the most common wastewater treatment plants. One of the most widely used methods in practice to reduce the content of finely dispersed impurities in water is their coagulation(precipitation in the form of special complexes - coagulants) followed by precipitation and filtration. After clarification, the water enters the clean water tanks.

water discoloration, those. the elimination or decolorization of various colored colloids or completely dissolved substances can be achieved by coagulation, the use of various oxidizing agents (chlorine and its derivatives, ozone, potassium permanganate) and sorbents (activated carbon, artificial resins).

Clarification by filtration with preliminary coagulation contributes to a significant reduction in bacterial contamination of water. However, among the microorganisms remaining in the water after water treatment, there may also be pathogens (bacilli of typhoid fever, tuberculosis and dysentery; cholera vibrio; polio and encephalitis viruses), which are a source of infectious diseases. For their final destruction, water intended for household purposes must be subjected to disinfection.

Disadvantages of coagulation, settling and filtering: costly and insufficiently effective methods of water treatment, and therefore require additional methods quality improvements.)

Water disinfection

Disinfection or disinfection is the final stage of the water treatment process. The goal is to suppress the vital activity of pathogenic microbes contained in the water. Since neither settling nor filtering gives complete release, chlorination and other methods described below are used to disinfect water.

In water treatment technology, a number of water disinfection methods are known, which can be classified into five main groups: thermal; sorption on active carbon; chemical(using strong oxidizing agents); oligodynamia(exposure to noble metal ions); physical(using ultrasound, radioactive radiation, ultraviolet rays). Of these methods, the methods of the third group are the most widely used. Chlorine, chlorine dioxide, ozone, iodine, potassium permanganate are used as oxidizing agents; hydrogen peroxide, sodium and calcium hypochlorite. In turn, of the listed oxidizing agents, preference is given in practice to chlorine, bleach, sodium hypochlorite. The choice of the method of water disinfection is made, guided by the consumption and quality of the treated water, the efficiency of its preliminary treatment, the conditions for the supply, transport and storage of reagents, the possibility of automating processes and mechanizing labor-intensive work.

Disinfection is subject to water that has passed the previous stages of treatment, coagulation, clarification and discoloration in a layer of suspended sediment or settling, filtering, since there are no particles in the filtrate, on the surface or inside of which bacteria and viruses can be in an adsorbed state, remaining outside the influence of disinfecting agents.

Disinfection of water with strong oxidizing agents.

Currently, at the facilities of housing and communal services for water disinfection, as a rule, chlorination water. If you drink tap water, you should know that it contains organochlorine compounds, the amount of which after the procedure for disinfecting water with chlorine reaches 300 μg / l. Moreover, this amount does not depend on the initial level of water pollution, these 300 substances are formed in water due to chlorination. Consumption of such drinking water can seriously affect health. The fact is that when organic substances are combined with chlorine, trihalomethanes are formed. These methane derivatives have a pronounced carcinogenic effect, which contributes to the formation cancer cells. When boiling chlorinated water, it produces the strongest poison - dioxin. To reduce the content of trihalomethanes in water, you can reduce the amount of chlorine used or replace it with other disinfectants, for example, using granular activated carbon for removal of the organic compounds which are formed at water purification. And, of course, we need more detailed control over the quality of drinking water.

In cases of high turbidity and color of natural waters, preliminary chlorination of water is widely used, however, this method of disinfection, as described above, is not only not effective enough, but also simply harmful to our body.

Disadvantages of chlorination: insufficiently effective and at the same time brings irreversible harm to health, since the formation of the carcinogen trihalomethanes contributes to the formation of cancer cells, and dioxin leads to severe poisoning of the body.

It is not economically feasible to disinfect water without chlorine, since alternative methods of water disinfection (for example, disinfection using ultraviolet radiation) are quite costly. An alternative to chlorination was proposed for disinfecting water with ozone.

Ozonation

A more modern water disinfection procedure is water purification using ozone. Really, ozonation Water at first glance is safer than chlorination, but it also has its drawbacks. Ozone is very unstable and quickly destroyed, so its bactericidal effect is short. But the water must still pass through plumbing system before ending up in our apartment. Along the way, she faces a lot of trouble. It's no secret that water pipes in Russian cities are extremely worn out.

In addition, ozone also reacts with many substances in water, such as phenol, and the resulting products are even more toxic than chlorophenols. Water ozonation turns out to be extremely dangerous in cases where bromine ions are present in the water, even in the smallest amounts, which are difficult to determine even in laboratory conditions. When ozonized, toxic compounds of bromine arise - bromides, which are dangerous to humans even in microdoses.

The method of water ozonation has proven itself very well for the treatment of large masses of water - in pools, in systems for collective use, i.e. where more thorough water disinfection is needed. But it must be remembered that ozone, as well as the products of its interaction with organochlorine, is poisonous, so the presence of large concentrations of organochlorine at the stage of water treatment can be extremely harmful and dangerous for the body.

Disadvantages of ozonation: the bactericidal effect is short, in reaction with phenol it is even more toxic than chlorophenolic ones, which is more dangerous for the body than chlorination.

Disinfection of water with bactericidal rays.

FINDINGS

All of the above methods are not effective enough, not always safe, and moreover, they are not economically feasible: firstly, they are expensive and very costly, requiring constant maintenance and repair costs, secondly, they have a limited service life, and thirdly, they consume a lot of energy resources. .

New technologies and innovative methods for improving water quality

The introduction of new technologies and innovative methods of water treatment makes it possible to solve a set of tasks that provide:

production of drinking water that meets the established standards and GOSTs, meets the requirements of consumers;
reliability of water purification and disinfection;
efficient uninterrupted and reliable operation of water treatment facilities;
reducing the cost of water treatment and water treatment;
saving reagents, electricity and water for own needs;
quality of water production.

New technologies for improving water quality include:

Membrane methods based modern technologies(including macrofiltration; microfiltration; ultrafiltration; nanofiltration; reverse osmosis). Used for desalination Wastewater, solve a complex of problems of water purification, but purified water does not mean that it is good for health. Moreover, these methods are expensive and energy intensive, requiring constant maintenance costs.

Reagentless methods of water treatment. Activation (structuring)liquids. There are many ways to activate water today (for example, magnetic and electromagnetic waves; waves of ultrasonic frequencies; cavitation; exposure to various minerals, resonant, etc.). The liquid structuring method provides a solution to a set of water treatment problems ( discoloration, softening, disinfection, degassing, iron removal of water etc.), while eliminating chemical water treatment.

Water quality indicators depend on the methods used for structuring the liquid and depend on the choice of technologies used, among which are:
- devices for magnetic water treatment;
- electromagnetic methods;
- cavitation method of water treatment;
- resonant wave water activation (non-contact processing based on piezocrystals).

Hydromagnetic systems (HMS) designed to treat water in a constant flow magnetic field special spatial configuration (used to neutralize scale in heat exchange equipment; to clarify water, for example, after chlorination). The principle of operation of the system is the magnetic interaction of metal ions present in water (magnetic resonance) and the simultaneous process of chemical crystallization. HMS is based on the cyclic effect on water supplied to heat exchangers by a magnetic field of a given configuration, created by high-energy magnets. The method of magnetic water treatment does not require any chemical reagents and is therefore environmentally friendly. But there are disadvantages. HMS uses powerful permanent magnets based on rare earth elements. They retain their properties (the strength of the magnetic field) for a very long time (tens of years). However, if they are overheated above 110 - 120 C, the magnetic properties may weaken. Therefore, HMS must be installed where the water temperature does not exceed these values. That is, before it is heated, on the return line.

Disadvantages of magnetic systems: the use of HMS is possible at a temperature not higher than 110 - 120 °WITH; not enough effective method; for complete purification, it is necessary to use it in combination with other methods, which, as a result, is not economically feasible.

Cavitation method of water treatment. Cavitation is the formation of cavities in a liquid (cavitational bubbles or caverns) filled with gas, steam or a mixture of them. essence cavitation- different phase state of water. Under conditions of cavitation, water changes from its natural state to steam. Cavitation occurs as a result of a local decrease in pressure in a liquid, which can occur either with an increase in its velocity (hydrodynamic cavitation) or with the passage of an acoustic wave during a rarefaction half-cycle (acoustic cavitation). In addition, a sharp (sudden) disappearance of cavitation bubbles leads to the formation of hydraulic shocks and, as a result, to the creation of a compression and tension wave in a liquid with an ultrasonic frequency. The method is used for cleaning from iron, hardness salts and other elements that exceed the MPC, but is poorly effective in water disinfection. At the same time, it significantly consumes electricity, which is expensive to maintain with consumable filter elements (resource from 500 to 6000 m 3 of water).

Disadvantages: consumes electricity, not efficient enough and expensive to maintain.

FINDINGS

The above methods are the most efficient and environmentally friendly compared to traditional methods water treatment and water treatment. But they have certain disadvantages: the complexity of installations, high cost, the need for consumables, difficulties in maintenance, significant areas are needed to install water treatment systems; insufficient efficiency, and in addition to this, restrictions on the use (restrictions on temperature, hardness, pH of water, etc.).

Methods of non-contact liquid activation (BOZh). resonance technologies.

Liquid processing is carried out in a non-contact way. One of the advantages of these methods is the structuring (or activation) of liquid media, which provides all of the above tasks by activating the natural properties of water without consuming electricity.

The most efficient technology in this area is NORMAQUA Technology ( resonant wave processing based on piezocrystals), non-contact, environmentally friendly, no electricity consumption, non-magnetic, maintenance-free, service life - at least 25 years. The technology was created on the basis of piezoceramic activators of liquid and gaseous media, which are resonators-inverters that emit ultra-low intensity waves. As with the action of electromagnetic and ultrasonic waves, unstable intermolecular bonds break under the influence of resonant vibrations, and water molecules line up in a natural physical and chemical structure in clusters.

The use of technology allows you to completely abandon chemical water treatment and expensive systems Supplies water treatment, and strike the perfect balance between maintaining the highest water quality and saving on operating costs.

Reduce the acidity of water (increase the pH level);
- save up to 30% of electricity on transfer pumps and wash out previously formed scale deposits by reducing the coefficient of friction of water (increasing the time of capillary suction);
- change the redox potential of water Eh;
- reduce overall stiffness;
- improve water quality: its biological activity, safety (disinfection up to 100%) and organoleptic.

1. What is meant by the steam-water cycle of boiler plants

For reliable and safe operation of the boiler, the circulation of water in it is important - its continuous movement in the liquid mixture along a certain closed circuit. As a result, intensive heat removal from the heating surface is ensured and local stagnation of steam and gas is eliminated, which protects the heating surface from unacceptable overheating, corrosion and prevents the boiler from breaking down. Circulation in boilers can be natural and forced (artificial), created with the help of pumps.

On fig. a diagram of the so-called circulation circuit is shown. Water is poured into the vessel, and the left wheel of the U-shaped tube is heated, steam is formed; the specific gravity of the mixture of steam and water will be less compared to the specific gravity in the right knee. The liquid in such conditions will not be in a state of equilibrium. For example, A - A, the pressure on the left will be less than on the right - a movement begins, which is called circulation. Steam will be released from the evaporation mirror, moving further out of the vessel, and feed water will be supplied to it in the same amount by weight.

To calculate the circulation, two equations are solved. The first expresses the material balance, the second the balance of forces.

G under \u003d G op kg / s, (170)

Where G under - the amount of water and steam moving in the lifting part of the circuit, in kg / s;

G op - the amount of water moving in the lower part, in kg / s.

N \u003d ∆ρ kg / m 2, (171)

where N is the total driving head, equal to h (γ in - γ cm), in kg;

∆ρ is the sum of hydraulic resistances in kg/m 2 , including the force of inertia, arising from the movement of steam-water emulsion and water through the office and eventually causing uniform movement at a certain speed.

Usually, the circulation ratio is selected within 10 - 50, and with a small heat load of the pipes, it is much more than 200 - 300.

m/s,

2. Reasons for the formation of deposits in heat exchangers

Various impurities contained in the heated and evaporated water can be released into the solid phase on the internal surfaces of steam generators, evaporators, steam converters and condensers of steam turbines in the form of scale, and inside the water mass - in the form of suspended sludge. However, it is impossible to draw a clear boundary between scale and sludge, since substances deposited on the heating surface in the form of scale can eventually turn into sludge and vice versa, under certain conditions, sludge can stick to the heating surface, forming scale.

Radiation heating surfaces of modern steam generators are intensively heated by a furnace torch. The heat flux density in them reaches 600–700 kW/m2, and local heat flows may be even higher. Therefore, even a short-term deterioration in the heat transfer coefficient from the wall to boiling water leads to such a significant increase in the temperature of the pipe wall (500–600 °C and higher) that the strength of the metal may not be sufficient to withstand the stresses that have arisen in it. The consequence of this is damage to the metal, characterized by the appearance of bulges, lead, and often rupture of pipes.

3. Describe the corrosion of steam boilers along the steam-water and gas paths

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1 . What is meant by the steam-water cycle of boiler mouthsnovok

The steam-water cycle is the period during which water turns into steam, and this period is repeated many times.

In modern boiler designs, the heating surface is made of separate tube bundles connected to drums and headers, which form a sufficient complex system closed circulation circuits.

To calculate the circulation, two equations are solved. The first expresses the material balance, the second the balance of forces.

The first equation is formulated as follows:

G under \u003d G op kg / s, (170)

Where G under - the amount of water and steam moving in the lifting part of the circuit, in kg / s;

G op - the amount of water moving in the lower part, in kg / s.

The force balance equation can be expressed as follows:

N=?? kg / m 2, (171)

where N is the total driving head, equal to h (? in -? cm), in kg;

The sum of hydraulic resistances in kg/m 2 , including the force of inertia, arising from the movement of steam-water emulsion and water through the office and eventually causing uniform movement at a certain speed.

The boiler circuit contains a large number of parallel pipes, and the conditions of their work cannot be completely identical for a number of reasons. In order to ensure uninterrupted circulation in all pipes of parallel-operating circuits and not to cause circulation overturning in any of them, it is necessary to increase the speed of water movement along the circuit, which is ensured by a certain circulation ratio K.

Usually, the circulation ratio is selected within 10 - 50, and with a small heat load of the pipes, it is much more than 200 - 300.

The water flow rate in the circuit, taking into account the circulation rate, is equal to

where D = steam (feed water) consumption of the calculated circuit in kg/h.

The speed of water at the entrance to the lifting part of the circuit can be determined from the equation

2 . Reasons for the formation ofzhenii in heat exchangers

Of the elements of the steam generator, heated screen pipes are most susceptible to contamination of internal surfaces. The formation of deposits on the inner surfaces of the steam-generating pipes entails a deterioration in heat transfer and, as a result, a dangerous overheating of the pipe metal.

Radiation heating surfaces of modern steam generators are intensively heated by a furnace torch. The heat flux density in them reaches 600-700 kW/m 2 , and local heat fluxes can be even higher. Therefore, even a short-term deterioration in the heat transfer coefficient from the wall to boiling water leads to such a significant increase in the temperature of the pipe wall (500-600 ° C and above) that the strength of the metal may not be sufficient to withstand the stresses that have arisen in it. The consequence of this is damage to the metal, characterized by the appearance of bulges, lead, and often rupture of pipes.

With sharp temperature fluctuations in the walls of the steam-generating pipes, which can occur during the operation of the steam generator, the scale exfoliates from the walls in the form of fragile and dense flakes, which are carried by the flow of circulating water to places with slow circulation. There, they are deposited in the form of a random accumulation of pieces of various sizes and shapes, cemented by sludge into more or less dense formations. If a drum-type steam generator has horizontal or slightly inclined sections of steam-generating pipes with sluggish circulation, then accumulation of deposits of loose sludge usually occurs in them. The narrowing of the cross section for the passage of water or the complete blockage of the steam pipes lead to a violation of circulation. In the so-called transition zone of a direct-flow steam generator up to the critical pressure, where the last remaining moisture evaporates and the steam is slightly overheated, deposits of calcium, magnesium compounds and corrosion products are formed.

Since the once-through steam generator is an effective trap for sparingly soluble compounds of calcium, magnesium, iron and copper. Then, with an increased content of them in the feed water, they quickly accumulate in the pipe part, which significantly reduces the duration of the working campaign of the steam generator.

In order to ensure minimal deposits both in the areas of maximum heat loads of the steam-generating pipes, as well as in the flow path of the turbines, it is necessary to strictly maintain the operational standards for the permissible content of certain impurities in the feed water. For this purpose, additional feed water is subjected to deep chemical purification or distillation in water treatment plants.

Improving the quality of condensates and feed water noticeably weakens the process of formation of operational deposits on the surface of steam-power equipment, but does not completely eliminate it. Therefore, in order to ensure the proper cleanliness of the heating surface, it is necessary, along with a one-time pre-start cleaning, to carry out periodic operational cleaning of the main and auxiliary equipment, and not only in the presence of systematic gross violations of the established water regime and in the absence of the effectiveness of anti-corrosion measures carried out at the TPP, but also in conditions of normal operation of the TPP. Operational cleaning is especially necessary for power units with once-through steam generators.

3 . Describe the corrosion of steam boilers bysteam-water and gas paths

Metals and alloys used for the manufacture of heat and power equipment have the ability to interact with the medium in contact with them (water, steam, gases) containing certain corrosion-aggressive impurities (oxygen, carbonic and other acids, alkalis, etc.).

Essential for disrupting the normal operation of a steam boiler is the interaction of substances dissolved in water with washing it with metal, as a result of which metal is destroyed, which, at known sizes, leads to accidents and failure of individual elements of the boiler. Such destruction of the metal by the environment is called corrosion. Corrosion always starts from the surface of the metal and gradually spreads to the depth.

Currently, two main groups of corrosion phenomena are distinguished: chemical and electrochemical corrosion.

Chemical corrosion refers to the destruction of metal as a result of its direct chemical interaction with the environment. In heat and power facilities, examples of chemical corrosion are: oxidation of the outer surface of heating by hot flue gases, corrosion of steel by superheated steam (the so-called steam-water corrosion), corrosion of metal by lubricants, etc.

Electrochemical corrosion, as its name shows, is associated not only with chemical processes, but also with the movement of electrons in interacting media, i.e. with the advent electric current. These processes occur when metal interacts with electrolyte solutions, which takes place in a steam boiler in which boiler water circulates, which is a solution of salts and alkalis decomposed into ions. Electrochemical corrosion also proceeds when the metal comes into contact with air (at normal temperature), which always contains water vapor, which, condensing on the metal surface in the form of a thin film of moisture, creates conditions for the occurrence of electrochemical corrosion.

The destruction of the metal begins, in essence, with the dissolution of iron, which consists in the fact that the iron atoms lose some of their electrons, leaving them in the metal, and thus turn into positively charged iron ions that pass into an aqueous solution. This process does not occur evenly over the entire surface of the metal washed by water. The fact is that chemically pure metals are usually not strong enough and therefore their alloys with other substances are mainly used in technology, as you know, cast iron and steel are alloys of iron with carbon. In addition, the steel structure is added to small quantities to improve its quality, silicon, manganese, chromium, nickel, etc.

According to the form of manifestation of corrosion, they distinguish: uniform corrosion, when the destruction of the metal occurs at approximately the same depth over the entire surface of the metal, and local corrosion. The latter has three main varieties: 1) pitting corrosion, in which metal corrosion develops in depth on a limited surface area approaching point manifestations, which is especially dangerous for boiler equipment (the formation of through fistulas as a result of such corrosion); 2) selective corrosion, when one of the constituent parts alloy; for example, in the pipes of turbine condensers made of brass (an alloy of copper and zinc), when they are cooled with sea water, zinc is removed from the brass, as a result of which the brass becomes brittle; 3) intergranular corrosion, which occurs mainly in insufficiently tight rivet and rolling joints of steam boilers with aggressive properties of boiler water with simultaneous excessive mechanical stresses in these areas of the metal. This type of corrosion is characterized by the appearance of cracks along the boundaries of metal crystals, which makes the metal brittle.

4 . What support the water-chemical regimes in the boilers and what do they depend on?

The normal mode of operation of steam boilers is such a mode, which provides:

a) obtaining clean steam; b) the absence of salt deposits (scale) on the heating surfaces of boilers and the scaling of the resulting sludge (the so-called secondary scale); c) prevention of all types of corrosion of boiler metal and steam condenser path carrying corrosion products to the boiler.

These requirements are met by taking measures in two main directions:

a) in the preparation of source water; b) when regulating the quality of boiler water.

The preparation of source water, depending on its quality and the requirements associated with the design of the boiler, can be carried out by:

a) pre-boiler treatment of water with the removal of suspended and organic substances, iron, scale formers (Ca, Mg), free and bound carbon dioxide, oxygen, reduction of alkalinity and salinity (liming, hydrogen - cationization or demineralization, etc.);

b) intra-boiler water treatment (with dosage of reagents or water treatment with a magnetic field with mandatory and reliable removal of sludge).

Boiler water quality is controlled by blowing boilers, a significant reduction in the size of the blowdown can be achieved by improving the boiler separation devices: staged evaporation, remote cyclones, steam washing with feed water. The totality of the implementation of the listed measures that ensure the normal operation of the boilers is called water - the chemical mode of operation of the boiler.

The use of any method of water treatment: inside the boiler, to the boiler with subsequent corrective treatment of chemically treated or feed water - requires the blowdown of steam boilers.

In the operating conditions of boilers, there are two methods of blowing boilers: periodic and continuous.

Periodic blowing from the lower points of the boiler is carried out to remove coarse sludge deposited in the lower collectors (drums) of the boiler or circuits with sluggish water circulation. It is produced according to the established schedule, depending on the degree of contamination of the boiler water, but at least once per shift.

Continuous blowdown of the boilers ensures the required purity of the steam, maintaining a certain salt composition of the boiler water.

5 . Describe the device of granularlightingx filters and how they work

Water clarification by filtration is widely used in water treatment technology; for this, the clarified water is filtered through a layer of granular material (quartz sand, crushed anthracite, expanded clay, etc.) loaded into the filter.

Classification of filters according to a number of main features:

filtration rate:

Slow (0.1 - 0.3 m/h);

Fast (5 - 12 m/h);

Super high speed (36 - 100 m/h);

pressure under which they work:

Open or non-pressure;

pressure;

number of filter layers:

Single layer;

Double layer;

Multilayer.

The most efficient and economical are multilayer filters, in which, in order to increase the dirt capacity and filtration efficiency, the load is made up of materials with different density and particle size: on top of the layer - large light particles, below - small heavy ones. With the downward direction of filtration, large contaminants are retained in the upper layer of the load, and the remaining small ones - in the lower one. Thus, the entire volume of the download works. Illumination filters are effective at retaining particles > 10 µm in size.

Water containing suspended particles, moving through a granular load that retains suspended particles, is clarified. The efficiency of the process depends on the physicist - chemical properties impurities, filter loading and hydrodynamic factors. Contaminants accumulate in the load thickness, the free volume of pores decreases and the hydraulic resistance of the load increases, which leads to an increase in pressure losses in the load.

In general, the filtration process can be conditionally divided into several stages: the transfer of particles from the water flow to the surface of the filter material; fixation of particles on the grains and in the gaps between them; detachment of fixed particles with their transition back into the water flow.

Extraction of impurities from water and fixing them on the grains of the load occurs under the action of adhesion forces. The sediment formed on the particles of the load has a fragile structure, which can be destroyed under the influence of hydrodynamic forces. Some of the previously adhered particles come off the grains of the load in the form of small flakes and are transferred to the subsequent layers of the load (suffusion), where they again linger in the pore channels. Thus, the process of water clarification should be considered as the total result of the process of adhesion and suffusion. Lightening in each elementary layer of the load occurs as long as the intensity of adhesion of particles exceeds the intensity of detachment.

As the upper layers of the load are saturated, the filtration process moves to the lower ones, the filtration zone, as it were, descends in the direction of flow from the area where the filter material is already saturated with pollution and the suffusion process predominates to the fresh load area. Then there comes a moment when the entire filter loading layer is saturated with water contaminants and the required degree of water clarification is not provided. The concentration of suspended solids at the outlet of the load begins to increase.

The time during which the clarification of water to a predetermined degree is achieved is called the time of the protective action of the load. When it reaches the limiting pressure loss, the lighting filter must be switched to the loosening washing mode, when the load is washed with a reverse flow of water, and the contaminants are discharged into the drain.

The ability of the filter to hold a coarse suspension depends mainly on its mass; fine suspension and colloidal particles - from surface forces. The charge of suspended particles is important, since colloidal particles of the same charge cannot combine into conglomerates, become larger and settle: the charge prevents them from approaching. This "alienation" of particles is overcome by artificial coagulation. As a rule, coagulation (sometimes, additionally, flocculation) is carried out in settling tanks - clarifiers. Often this process is combined with water softening by liming, or soda - liming, or caustic soda softening.

In conventional lighting filters, film filtering is most often observed. Volumetric filtration is organized in two-layer filters and in the so-called contact clarifiers. The bottom layer of quartz sand with a size of 0.65 - 0.75 mm and the top layer of anthracite with a grain size of 1.0 - 1.25 mm are poured into the filter. No film is formed on the upper surface of the layer of coarse anthracite grains. Suspended substances that have passed through the anthracite layer are retained by the bottom layer of sand.

When loosening the filter, the layers of sand and anthracite do not mix, since the density of anthracite is half that of quartz sand.

6 . OpLook for the softening process inodes by the cation exchange method

According to the theory of electrolytic dissociation, the molecules of certain substances in an aqueous solution decompose into positively and negatively charged ions - cations and anions.

When such a solution passes through a filter containing a sparingly soluble material (cation exchanger) capable of absorbing solution cations, including Ca and Mg, and releasing Na or H cations instead of them, water softening occurs. Water is almost completely freed from Ca and Mg, and its hardness is reduced to 0.1 °

Na - kathionization. With this method, calcium and magnesium salts dissolved in water, when filtered through a cation exchange material, exchange Ca and Mg for Na; as a result, only sodium salts with high solubility are obtained. The formula of the cationic material is conventionally denoted by the letter R.

Cationic materials are: glauconite, sulfocarbon and synthetic resins. Sulfocoal, which is obtained after the treatment of brown or hard coal with fuming sulfuric acid, is currently the most widely used.

The capacity of the cation exchange material is the limit of its exchange capacity, after which, as a result of the consumption of Na cations, they must be restored by regeneration.

The capacity is measured in ton - degrees (t-deg) scale formers, counting per 1 m 3 of cationic material. Ton - degrees are obtained by multiplying the consumption of treated water, expressed in tons, by the hardness of this water in degrees of hardness.

Regeneration is carried out with a 5 - 10% solution table salt passed through the cationic material.

A characteristic feature of Na - cationization is the absence of salts that precipitate. The anions of hardness salts are wholly sent to the boiler. This circumstance makes it necessary to increase the amount of purge water. Water softening during Na - cationization is quite deep, the hardness of the feed water can be brought to 0 ° (practically 0.05-01 °), the alkalinity does not differ from the carbonate hardness of the source water.

The disadvantages of Na - cationization include obtaining increased alkalinity in cases where there is a significant amount of salts of temporary hardness in the source water.

Limited to one Na - cationization is possible when the carbonate hardness of water does not exceed 3-6 °. Otherwise, it is necessary to significantly increase the amount of purge water, which will already create large heat losses. Usually, the amount of blowdown water does not exceed 5-10% of its total flow used to feed the boiler.

The cationization method requires very simple maintenance and is available to ordinary boiler room personnel without the additional involvement of a chemist.

Cation filter design

H - Na-toanionization. If the cationite filter filled with sulfocoal is regenerated not with a solution of common salt, but with a solution of sulfuric acid, then the exchange will occur between the Ca and Mg cations in the treated water and the H cations of sulfocoal.

Water prepared in this way, also having a negligible hardness, simultaneously becomes acidic and thus unsuitable for feeding steam boilers, and the acidity of the water is equal to the non-carbonate hardness of the water.

By combining together Na and H - cationic water softening, good results can be obtained. The hardness of water prepared by H-Na - cation exchange method does not exceed 0.1 ° with an alkalinity of 4-5 °.

7 . Describe the principlecircuit water treatment schemes

The implementation of the necessary changes in the composition of the treated water is possible according to various technological schemes, then the choice of one of them is made on the basis of comparative techniques - economic calculations for the planned scheme options.

As a result of the chemical treatment of natural waters carried out at water treatment plants, the following main changes in their composition may occur: 1) clarification of water; 2) water softening; 3) reduction of water alkalinity; 4) decrease in salinity of water; 5) complete desalination of water; 6) water degassing. Water treatment schemes required for implementation

listed changes in its composition may include various processes, which are reduced to the following three main groups: 1) methods of deposition; 2) mechanical water filtration; 3) ion-exchange water filtration.

The use of technological schemes of water treatment plants usually involves a combination of different methods of water treatment.

The figures show possible schemes of combined water treatment plants using these three categories of water treatment processes. In these schemes, only the main apparatuses are given. Without auxiliary equipment, and second and third stage filters are not indicated.

Scheme of water treatment plants

1-raw water; 2-illuminator; 3-mechanical filter; 4-intermediate tank; 5-pump; 6-coagulant dispenser; 7-Na - cationic filter; 8- H - cationic filter; 9 - calciner; 10 - OH - anion filter; 11 - treated water.

Ion-exchange filtration is a mandatory final stage of water treatment for all possible schemes and is carried out in the form of Na - cationization, H-Na-cationization and H-OH - ionization of water. Clarifier 2 provides for two main options for its use: 1) water clarification, when the processes of coagulation and settling of water are carried out in it, and 2) water softening, when, in addition to coagulation, liming is carried out in it, as well as magnesia desiliconization of water simultaneously with liming.

Depending on the characteristics of natural waters in terms of the content of suspended solids in them, three groups of technological schemes for their treatment are possible:

1) Underground artesian waters (marked in Fig. 1a), in which there are practically no suspended solids, do not require their clarification, and therefore the treatment of such waters can be limited only by ion-exchange filtration according to one of three schemes, depending on the requirements for treated water: a ) Na - cationization, if only water softening is required; b) H-Na - cationization, if, in addition to softening, a decrease in alkalinity or a decrease in the salinity of water is required; c) H-OH - ionization, if deep desalination of water is required.

2) surface waters with a low content of suspended solids (indicated in Fig. 1b) can be treated according to the so-called direct-flow pressure schemes, in which coagulation and clarification in mechanical filters are combined with one of the ion-exchange filtration schemes.

3) surface waters with a relatively large amount of suspended solids (indicated in Fig. 1c), are released from them during clarification, after which they are subjected to mechanical filtration and then combined with one of the ion-exchange filtration schemes. At the same time, often. In order to unload the ion-exchange part of the water treatment plant, simultaneously with coagulation, partial water softening and reduction of its salt content by liming and magnesia desiliconization are carried out in the clarifier. Such combined schemes are especially appropriate for the treatment of highly mineralized waters, since even with their partial desalination by the ion exchange method, large

Decision:

Determine the interwash period of the filter, h

where: h 0 - filter layer height, 1.2 m

Gy is the dirt holding capacity of the filter material, 3.5 kg/m 3 .

The value of Gr can vary widely depending on the nature of suspended solids, their fractional composition, filter material, etc. In calculations, Gr = 3? 4 kg / m 3, on average 3.5 kg / m 3,

U p - filtration speed, 4.1 m/h,

C in - concentration, suspended solids, 7 mg / l,

The number of filter washes per day is determined by the formula:

where: T 0 - interwash period, 146.34 h,

t 0 - downtime of the filter for washing, usually 0.3 - 0.5 h,

Determine the required filtering area:

where: U-filtering speed, 4.1 m/h,

Q - Productivity, 15 m 3 / h,

In accordance with the rules and regulations for the design of water treatment plants, the number of filters must be at least three, then the area of one filter will be:

where: m is the number of filters.

Based on the found area of one filter, we find the required filter diameter according to the table: diameter d \u003d 1500 mm, filtering area f \u003d 1.72 m 2.

Specify the number of filters:

If the number of filters is less than the interwash period m 0 ? T 0 +t 0 (in our example 2

The calculation of the filter includes the determination of water consumption for own needs, i.e. for washing the filter and for washing the filter after washing.

Water consumption for filter washing and loosening is determined by the formula:

where: i is the intensity of loosening, l / (s * m 2); usually i \u003d 12 l / (s * m 2);

t - flushing time, min. t = 15 min.

We determine the average water consumption for washing operating filters according to the formula:

Let us determine the flow rate for the descent into the drainage of the first filter at a speed of 4 m/h for 10 minutes before putting it into operation:

Average water consumption for cleaning operating filters:

The required amount of water for the filtration plant, taking into account the consumption for own needs:

Q p \u003d g cf + g cf.elev + Q

Q p \u003d 0.9 + 0.018 + 15 \u003d 15.9 m 3 / h

Literature

1. "Water treatment". V.F. Vikhrev and M.S. Shkrob. Moscow 1973.

2. "Handbook on water treatment of boiler plants". O.V. Lifshits. Moscow 1976

3. "Water treatment". B.N. Frog, A.P. Levchenko. Moscow 1996.

4. "Water treatment". CM. Gurvich. Moscow 1961.

The main stages of water treatment

Mechanical water purification. This is preparatory stage water treatment, aimed at removing large (visible) polluting particles from the water - sand, rust, plankton, silt and other heavy suspensions. It is carried out before supplying water to the main treatment plant using gratings with a mesh of various diameters and rotating screens.
Chemical water treatment. It is produced in order to bring water quality to standard indicators. For this, various technological methods are used: clarification, coagulation, settling, filtration, disinfection, demineralization, softening.

Lightening required mainly for surface waters. Held on initial stage purification of drinking water in the reaction chamber and consists in adding a chlorine-containing preparation and a coagulant to the volume of treated water. Chlorine contributes to the destruction of organic substances, mostly represented by humic and fulvic acids, which are inherent in surface waters and give them a characteristic greenish-brown color.

Coagulation It is aimed at purifying water from suspensions and colloidal impurities invisible to the eye. Coagulants, which are aluminum salts, help the smallest particles of organic matter (plankton, microorganisms, large protein molecules) in suspension stick together and turn them into heavy flakes, which then precipitate. To enhance flocculation, flocculants, chemicals of various brands, can be added.

settling water occurs in tanks with slow flow and overflow mechanism, where the lower layer of liquid moves more slowly than the upper one. In this case, the overall speed of water movement slows down, and conditions are created for the precipitation of heavy polluting particles.

Filtration on carbon filters or carbonization, helps to get rid of 95% of the impurities in the water, both chemical and biological properties. Previously, water was filtered on cartridge filters with pressed activated carbons. But this method is quite laborious and requires frequent and costly regeneration of the filter material. At the present stage, it is promising to use granular (GAC) or powdered (PAC) activated carbons, which are poured into water in the carbonization unit and mixed with the treated water. Studies have shown that this method is much more efficient than filtering through block filters, and also less expensive. PAHs help eliminate pollution from chemicals, heavy metals, organics, and last but not least, surfactants. Filtration with activated carbons is technologically available at any type of waterworks.

Disinfection It is used on all types of water pipelines without exception to eliminate the epidemic danger of drinking water. Nowadays, disinfection methods provide a large selection of different methods and disinfectants, but one of the components is invariably chlorine, due to its ability to remain active in the distribution network and disinfect water pipes.

Demineralization in industrial scale involves the removal of excess amounts of iron and manganese from the water (iron removal and demanganation, respectively).

The increased content of iron changes the organoleptic properties of water, leads to its coloring in yellow-brown color, gives an unpleasant "metallic" taste. Iron precipitates in pipes, creating conditions for their further contamination with biological agents, stains linen during washing, and negatively affects plumbing equipment. In addition, high concentrations of iron and manganese can cause diseases of the gastrointestinal tract, kidneys and blood. An excess amount of iron is usually accompanied by a high content of manganese and hydrogen sulfide.

On public water supply systems, iron removal is carried out by aeration. In this case, ferrous iron is oxidized to trivalent and precipitates in the form of rust flakes. Further, it can be eliminated using filters with different loadings.

Aeration is carried out in two ways:

Pressure aeration - an air mixture is supplied to the contact chamber in the center through a pipe reaching half of the chamber. Then the water column is bubbling with bubbles of the air mixture, which oxidizes metal impurities and gases. The aeration column is not completely filled with water, there is an air cushion above the surface. Its task is to mitigate water hammer and increase the aeration area.
Non-pressure aeration - carried out with the help of shower installations. In special chambers, water is sprayed using water ejectors, which significantly increases the contact area of water with air.

In addition, iron is intensively oxidized when water is treated with chlorine and ozone.

Manganese is removed from water by filtration through modified media or by adding oxidants such as potassium permanganate.

Softening water is carried out to eliminate hardness salts - calcium and magnesium carbonates. For this, filters are used loaded with acidic or alkaline cation exchangers or anion exchangers, replacing calcium and magnesium ions with neutral sodium. This is a rather expensive method, therefore it is used most often at local water treatment plants.

Water supply to the distribution network.

After passing through the full complex of treatment facilities at the waterworks, the water becomes potable. Then it is served to the consumer by the system water pipes, the state of which in most cases leaves much to be desired. Therefore, more and more often the question is raised about the need for post-treatment of tap drinking water and not only bringing it to regulatory requirements, but also imparting health-promoting qualities.

Let me remind you what a block heat point is and how it differs from a conventional ITP. ITP or full name individual heating point this is a set of equipment and devices that allows you to receive, take into account, regulate, distribute and deliver heat to end consumers, that is, to you and me and to our apartments. It is usually located in the basement at the entrance to the residential apartment house.

The heating point is manufactured according to the drawings developed by the design organization, agreed with all interested parties and, first of all, the heat supply organization, since the basis for the design are the specifications (technical specifications) issued by this very organization.

The installation of a heat point is usually carried out in the same basement, one might say in a handicraft way, right on the knee, of course, if the same heat point is made in the factory, its quality will be an order of magnitude higher, and meanwhile, despite all the recommendations and regulations of our legislation use of block heating points so far not widespread.

A fair question - why are block heat points not being properly used?

As they say .

There are several such reasons, let's try to analyze each.

Reason 1- project does not want to coordinate the heat supply organization or as we usually call it - thermal networks.

Why? The thing is that designers go the easiest way. Wanting to reduce the cost of project documentation (in order to win the auction), they simply send a request for the manufacture of a block heat point to the manufacturer, and put the drawings of the commercial offer into the project under the proud name - ITP.
The manufacturer also issues standard documentation, without proper reference to local conditions and loads. It is not possible to make one product for all occasions. As a result, such a project is not agreed upon by the energy supplying organization or is agreed under pressure from government or money.

Reason 2- in most old-built houses (and in new ones too), a block heat point cannot be installed due to its size and weight. Without disassembly, you can’t drag it into the basement. Of course, no one will disassemble and re-mount it either, only weight and connection are taken into account in the installation price. So a “parody” of a block ITP is being made right on the spot, from completely different equipment (by the way, this is allowed by the rules of the auction and, moreover, it is prescribed for an alternative). As a result, we only get a discredit of the idea of creating a heat point in an industrial environment.

Reason 3– see who is the manufacturer of block heat points.
Manufacturer plate heat exchangers, its purpose is the marketing of its products.
The manufacturer of heat meters - the goal is also clear and the manufacturer of automation equipment for thermal processes, the goal is also clear and this is by no means a concern for our heat savings, but only for the sale of our products.
Where such conclusions you ask, from the analysis of commercial proposals. In the block heat points offered for sale, there is always a surplus of the supplier's products.

Considering that block ITP require mandatory fixed costs for electricity and main maintenance, while access to individual elements for repair is almost always difficult, it is clear that the introduction of block ITPs, despite all their advantages, is constrained.

What to do, how to achieve the introduction of the advanced idea of installing modern block heat points that save heat in our homes.

Everything is quite simple, for this you need:

Stop saving on project documentation, the designer should prepare a schematic diagram of the ITP, link it to the loads and temperature conditions, coordinate with the power supply organization and only after that place an order with the manufacturer.
The same should apply, namely, the draft metering unit developed in accordance with all the rules (meaning the rules for commercial heat metering) and agreed with the heat supplier is necessary transfer the manufacturer of block heat points .
Suppliers of block heat points must supply their products strictly according to the ITP schematic diagrams provided to them, with a set of working documentation on which it is made.
When preparing estimates for installation or overhaul it is necessary to take into account local conditions, if the block heat point cannot be installed without dismantling, then it must be disassembled and reassembled, taking this into account in the installation price, for this the working documentation of the manufacturer is useful.
Exclude from the auction requirements permission to use alternative materials, if the project is developed, change design solutions without the consent of the designers to prohibit.
Restore architectural supervision over the implementation of projects.
Before concluding contracts, pay attention not only to the membership of the applicant in the SRO, but also to the certification of direct executors in the technical supervision bodies, since block heat points are not internal engineering networks residential buildings, and to the device of thermal networks.

The measures listed above will help real, and not on paper, the introduction of block heat points in our homes, which in turn will improve

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The main stages of water treatment

Water supply to the distribution network.

A fair question - why are block heat points not being properly used?

What to do, how to achieve the introduction of the advanced idea of ​​installing modern block heat points that save heat in our homes.

What to do, how to achieve the introduction of the advanced idea of installing modern block heat points that save heat in our homes.